<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .active {
        color: red;
      }
    </style>
  </head>

  <body>
    <div id="app">
      <!-- <h2 class="active">{{message}}</h2> -->
      <!-- <h2 :class="active">{{message}}</h2> -->

      <!-- <h2 v-bind:class="{key1: value1, key2: value2}">{{message}}</h2> -->
      <!-- <h2 v-bind:class="{类名1: true, 类名2: bollean}">{{message}}</h2> -->
      <h2 class="title" v-bind:class="{active: isActive, line: isLine}">
        {{message}}
      </h2>
      <h2 class="title" v-bind:class="getClasses()">{{message}}</h2>
      <button v-on:click="btnClick">按钮</button>
    </div>

    <script src="../js/vue.js"></script>
    <script>
      const app = new Vue({
        el: '#app',
        data: {
          message: '你好',
          isActive: true,
          isLine: true
        },
        methods: {
          btnClick: function () {
            this.isActive = !this.isActive
          },
          getClasses: function () {
            return {
              active: this.isActive,
              line: this.isLine
            }
          }
        }
      })
    </script>
  </body>
</html>
